Malformation of the outer ear, or pinna, known as microtia does not occur in all patients with atresia. In those patients with microtia, there is always an abnormality of the ear canal. Some patients have normal outer ears and no ear canal development caused by a genetic condition known as 18Q(-) Syndrome, which requires further investigation.
A score for the outer ear development is given as grade 1 (normal), grade 2 (mild malformation and retention of the tragus), grade 3 (poorly developed outer ear), or grade 4 (no development of the outer ear). Grades 3 and 4 are typically reconstructed. Some grade 2 abnormalities are reconstructed and some left as is after an ear canal is created in the normal position.